Kids are consuming fewer calories a day now than they did a decade ago, according to government data out Thursday.

Calorie intake for boys ages 2 to 19 dropped by 158 calories from 2000 to 2010. For girls the same age it fell by 76 calories.

The average calorie intake for boys was 2,258 calories in 2000 vs. 2,100 in 2010. For girls the intake dropped from 1,831 calories in 2000 to 1,755 in 2010.

"This is a surprise," says the study's lead author, Bethene Ervin, a nutritional epidemiologist with the National Center for Health Statistics, part of the Centers for Disease Control and Prevention. Energy intake among adults during this time period did not change, she says.

The recommended caloric intake for children and teens varies greatly, from 1,000 to 3,200 calories a day, depending on age, gender and activity level.

The findings come "as we're seeing a leveling off of obesity in recent years," says the report's senior author, Cynthia Ogden, an epidemiologist with the National Center for Health Statistics. "Obesity in children and teens in recent years has remained at about 17%."

The new statistics are from the National Health and Nutrition Examination Survey, which evaluates food and beverage intake based on data from in-person interviews. The results are from more than 22,000 interviews. Parents answered questions for children ages 2 to 11; adolescents answered the questions themselves.

Other findings:

• The percentage of calories from protein — eggs, meat, fish, nuts — increased slightly from roughly 13.5% to 14.5% for children and teens.

• The percentage of calories from total fat stayed about the same at about 31%.

Registered dietitian Elizabeth Ward, author of MyPlate for Moms, How to Feed Yourself & Your Family Better, says: "Calories count, but diet quality matters, too. Kids may be eating less, but that's not the whole story.

"Every day, children need two to three servings of low-fat dairy foods, upwards of five servings of fruits and vegetables, at least three servings of whole grains, and protein foods such as lean meats, poultry, eggs, and beans."